Regional adenosine-induced hypoperfusion without hyperenhancement on LGE-MRI in young HCM patients: comparison to subjects at risk of HCM and healthy volunteers
Robert Jablonowski
0
Eva Fernlund
1
Anthony H Aletras
0
Henrik Engblom
0
Einar Heiberg
0
2
Petru Liuba
1
Hkan Arheden
0
Marcus Carlsson
0
From
th Annual SCMR Scientific Sessions Nice
France.
February
0
Cardiac MR group Lund, Dept of Clinical Physiology, Lund University
,
Lund
,
Sweden
1
Dept. of Pediatric Cardiology, Lund University Hospital, Lund University
,
Lund
,
Sweden
2
Dept. of Biomedical Engineering, Faculty of Engineering, Lund University
,
Lund
,
Sweden
-
Background
The relation between hypoperfusion and fibrosis is not
completely understood in hypertrophic cardiomyopathy
(HCM). One hypothesis is that hypoperfusion is a
primary cause of fibrosis. Therefore, the aim of this study
was to use cardiac magnetic resonance (CMR) to 1)
measure if regional perfusion is decreased in young
patients with HCM and in subjects at risk of HCM
compared to normal controls and 2) determine if
regional myocardial perfusion is decreased in areas with left
ventricular hypertrophy (LVH) without detectable
fibrosis.
Methods
Study participants were divided into either 1) HCM
patients (wall thickness>13mm or >3SD on z-score with
echocardiography and/or fibrosis), 2) HCM-risk subjects
(HCM present among first-degree relatives, but without
LVH/fibrosis on CMR), and 3) healthy controls.
Regional perfusion imaging and late gadolinium
enhancement (LGE)-CMR was performed on a Philips
Achieva 1.5T with a 32-channel coil. Perfusion images
were acquired during adenosine (140g/kg/min)
hyperemia and at rest and divided into 16 segments (Figure 1).
Maximum upslope (ratio of the perfusion stress and rest
values normalized for LV input function) was used for
semi-quantitative analysis. Hypertrophic LV segments
were analyzed by co-registration with corresponding LGE
short-axis images. Differences with p<0.05 were
considered statistically significant.
Results
Twenty-six young subjects were included, seven patients
with HCM (226 years), eleven subjects at risk of HCM
(194 years) and eight controls (225 years). The LV
mass was larger in HCM patients compared to
HCMrisk and normal subjects (8543 vs 466, 539g/m2,
p<0.05) and the end-diastolic and end-systolic volumes
were smaller for HCM-patients and subjects at risk
compared to normal subjects (p<0.05).
The extent and severity of hypoperfused myocardium in
HCM patients during adenosine was larger compared to
rest and had larger extent compared to fibrosis (Figure 1).
Analysis of perfusion showed no significant difference
between controls and HCM-risk subjects (2.40.5 vs
2.30.6, p=0.09) (Figure 2). Segments with hypertrophy
and no fibrosis in HCM-patients showed decreased
perfusion compared to segments without hypertrophy (1.30.3
vs. 2.10.5, p<0.0001). Segments with both hypertrophy
and fibrosis showed even lower perfusion (0.90.3,
p<0.0001).
Conclusions
This study has demonstrated decreased regional
perfusion in myocardium with hypertrophy compared to
non-hypertrophied myocardium and even lower
perfusion in hypertrophy with fibrosis in young HCM
patients. Subjects at risk of HCM showed normal
regional perfusion during adenosine. The region of
hyperemia-induced hypoperfusion has a larger extent than the
Figure 1 Short-axis perfusion images of the left ventricle at rest (left), adenosine stress (middle) and corresponding late gadolinium
enhancement (LGE) image (right) in one representative patient with hypertrophic cardiomyopathy. The extent and severity of ischemic areas
(dashed white lines) was larger at adenosine stress compared to rest. The extent was larger for both ischemic areas compared to fibrosis (full
white line). Green line=epicardium, red line=endocardium.
Figure 2 Regional myocardial perfusion expressed as up-slope ratio
(meanSD) in normal controls (n=105 segments), patients at risk of
hypertrophic cardiomyopathy (HCM-risk) (n=151 segments) and
HCM-patients, subdivided into three groups of segments: (i) without
left ventricular hypertrophy (LVH) and fibrosis (LGE) (LVH-/LGE-,
n=60 segments), (ii) segments with LVH but without fibrosis (LVH
+/LGE-, n=22 segments) and (iii) segments with LVH and fibrosis
(LVH+/LGE+, n=22 segments).
fibrotic myocardium on LGE. This supports the
hypothesis that myocardial hypoperfusion is primary and that
fibrosis is caused by replacement fibrosis.
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